1. Field of the Invention
The present invention relates to a method and an apparatus for removing an image forming substance from an image holding member in which the image forming substance is stably attached onto the image holding member by an image forming apparatus such as a copying machine, a facsimile telegraph, a printer, etc., and is separated and removed from this image holding member.
2. Description of the Related Art
There are generally various kinds of known image forming substance removing methods and apparatuses for removing an image forming substance such as toner from a sheet of paper as a recorded image holding member. For example, Japanese Patent Application Laying Open (KOKAI) No. 1-101576 shows an image forming substance removing method using a solvent. In this removing method, toner is attached onto a sheet of paper and this paper sheet is dipped into a soluble solvent of toner resin. Then, a supersonic wave is vibrated in this paper sheet so that the toner dissolved into the solvent is separated from a paper face. Japanese Patent Application Laying Open (KOKAI) No. 4-300395 shows another image forming substance removing method. In this removing method, toner is dissolved in a printed portion of a sheet of used paper by attaching a solvent to this printed portion using a dipping, spraying or coating method, etc. The dissolved toner is removed from the printed portion by a method using cleaning, air suction, absorbent contact, mechanical separation or electrostatic adsorption, etc.
In contrast to this, for example, Japanese Patent Application Laying Open (KOKAI) No. 2-255195 shows an image forming substance removing method in which no solvent is used. In this removing method, thermally melted ink or toner is attached onto a printed member by an electrophotographic system or a thermal transfer system. In this printed member, a mold-releasing agent is coated and attached onto a supporting member. This printed member is then overlapped with an ink separating member and is moved between a heating roller and a pressure roller. After this printed member is cooled, the ink separating member is separated from the printed member so that the ink or toner is attached onto the ink separating member and is removed from the printed member. Japanese Patent Application Laying Open (KOKAI) No. 4-64472 shows an eraser having at least an endless sheet, a heating roller, a cooling roller, a pressing roller and a driving section for operating these members in association with each other. The endless sheet has thermally melted resin on a surface thereof. The heating and cooling rollers support and rotate this endless sheet. The pressing roller presses a sheet of erasable paper having a mold-released surface against thermally softened or melted resin. Japanese Patent Application Laying Open (KOKAI) No. 4-82983 shows an image forming substance removing apparatus having two parallel rollers, a heater, a scraper and a separator. The two parallel rollers come in press contact with each other and are rotated such that a sheet of paper passes through a press contact portion of these rollers. The heater heats at least one of these two rollers. The scraper separates the paper sheet passing through the press contact portion from the parallel rollers. The separator removes an image forming substance attached onto the parallel rollers from the parallel rollers.
No solvent is used in the above removing methods and apparatus. Each of the removing method and apparatus can be used to remove the image forming substance from a recorded image holding member in which an image is recorded onto a sheet of normal paper having exposed paper fibers on a surface thereof. In this case, for example, the image forming substance having thermally melted resin as a principal component is melted and attached onto the image holding member in a fixing process of the electrophotographic system. Therefore, the image forming substance is strongly fixed to paper fibers on a surface of the image holding member. Accordingly, when the image forming substance is removed from the image holding member, the paper fibers are removed from this surface together with the image forming substance so that the paper sheet is damaged and a paper quality is reduced. In particular, when the above ink separating member, the endless sheet or each of the rollers is heated and pressurized to efficiently remove the image forming substance from the image holding member, there is a case in which fixing force between the image forming substance and the image holding member is conversely increased in accordance with various kinds of conditions. In this case, it is difficult to remove the image forming substance from the image holding member.
Therefore, for example, inventors of this application proposed an image forming substance removing method in Japanese patent application No. 4-255916. In this removing method, at least one kind of water or aqueous solution is selected from a group of water as an unstabilizing agent, an aqueous solution including a surfactant, an aqueous solution including a water-soluble polymer, and an aqueous solution including a surfactant and a water-soluble polymer. This selected water or aqueous solution is held in a recorded image holding member. The image forming substance is heated or pressurized and is adhered to a separating member so that the image forming substance is separated from the image holding member. In this removing method, only the image forming substance can be removed from the image holding member without relatively reducing a paper quality of the image holding member.
In this general apparatus for removing the image forming substance from the image holding member, the unstabilizing agent is provided to the recorded image holding member. Thereafter, the image forming substance is separated from the image holding member through the separating member by heating or pressurizing adhesion of the image forming substance to the separating member. In this case, when the image holding member is stamped in red seal-ink, a Shachihata (a trade name in Japan) stamp, etc. and is additionally written with a sign pen, a ball-point pen, a lead pencil, a red pencil, etc., there is a case in which no image forming substance forming an image by each of the stamp and the additional writing can be removed from the image forming substance. Accordingly, the image forming substance is left on the image holding member in this case. The following problems are caused in a certain case when an image of the image forming substance cannot be removed from the image holding member by the above image forming substance removing apparatus and is left on this image holding member. For example, there is a fear of reusing the image holding member as a new image holding member although the unremoved image is left on this image holding member. When the image holding member having the unremoved image is not reused but is thrown away, there is also a fear of causing a secrecy problem. Further, there is a fear of intentionally abusing (altering and forging) the image holding member having the unremoved image such as a seal print, a signature, etc. When only an image holding member having no unremoved image is reused, it is necessary to sort and discriminate this image holding member from the image holding member having the unremoved image when the image holding member having the unremoved image is included within many image holding members processed with respect to removal of the image forming substance.